It is proposed to study: (1) the molecular properties of oxidation-reduction components of steroid hydroxylases in adrenal cortex mitochondria; (2) the superoxide (a toxic substance) generation by the complex of adrenodoxin reductase with adrenodoxin; (3) the purification and properties of cytochrome P-450 from this mitochondria, and its comparison with microsomal cytochrome P-450; (4) the topology of the redox components in this mitochondrial inner membrane and the effects of ACTH on the membrane structure; (5) the purification and properties of ACTH-stimulated enzymes: cholesterol esterase and ornithine decarboxylase. The method of procedures used in this proposal are mainly the extensive purification and characterization of the enzymes and proteins. By means of reconstitution of these characterized components into a system close to that in the native system of adrenal cortex mitochondria, we hope to be able to understand the relationship between the steroidogenesis and the action of ACTH in adrenal cortex. Additionally, we hope to understand the mechanism of superoxide generation by this system in relation to its toxic roles on biological systems.